fix: follow symlinks in list_files_recursively with cycle detection

list_files_recursively now uses followlinks=True so symlinked
directories under input/ and output/ roots are traversed, matching
the existing behavior of folder_paths.recursive_search for models.

Tracks (st_dev, st_ino) pairs of visited directories to detect and
break circular symlink loops safely.

Amp-Thread-ID: https://ampcode.com/threads/T-019c9220-21b8-7678-b428-9215ff1bb011
Co-authored-by: Amp <amp@ampcode.com>

app/assets/services/file_utils.py

@@ -42,14 +42,26 @@ def is_visible(name: str) -> bool:
 
 
 def list_files_recursively(base_dir: str) -> list[str]:
-    """Recursively list all files in a directory."""
+    """Recursively list all files in a directory, following symlinks."""
     out: list[str] = []
     base_abs = os.path.abspath(base_dir)
     if not os.path.isdir(base_abs):
         return out
+    # Track seen real directory identities to prevent circular symlink loops
+    seen_dirs: set[tuple[int, int]] = set()
     for dirpath, subdirs, filenames in os.walk(
-        base_abs, topdown=True, followlinks=False
+        base_abs, topdown=True, followlinks=True
     ):
+        try:
+            st = os.stat(dirpath)
+            dir_id = (st.st_dev, st.st_ino)
+        except OSError:
+            subdirs.clear()
+            continue
+        if dir_id in seen_dirs:
+            subdirs.clear()
+            continue
+        seen_dirs.add(dir_id)
         subdirs[:] = [d for d in subdirs if is_visible(d)]
         for name in filenames:
             if not is_visible(name):